UniFi's Advanced Wi-Fi Settings Explained : Ubiquiti
UniFi's Advanced Wi-Fi Settings Explained — McCann Tech
a really good breakdown of this stuff
How to fix an unresponsive Unifi Cloud Key | David Mello
some of this seems out of date or maybe just doesn't apply to my set up. I needed to run the reset command:
/sbin/ubnt-systool reset2defaults
Then I logged in to the web ui,logged in with root/ubnt and ran updates.